Control valve with area independent pressure sensing

Abstract

A control valve includes a valve body with a longitudinal bore into which a first port, a second port, and a workport communicate. A valve element is slideably received within the longitudinal bore and has a valve element bore extending inwardly from one end. An aperture extends through the valve element to provide a fluid path between the workport and selectively the first port and the second port in different positions of the valve element in the longitudinal bore. A slug of solid material is received within the valve element bore and is operatively connected to transfer a force to a stationary component of the control valve without the force being applied to the valve element. This arrangement results in force due to pressure in the longitudinal bore acting on only an annular surface at the one end of the valve element.

The invention claimed is: 
     
       1. An electrohydraulic control valve comprising:
 a valve body having a first bore with a first port and a workport in communication with the first bore; 
 a valve element slideably received within the first bore for controlling fluid flow between the first port and the workport, and having a first end from which a valve element bore extends into the valve element; 
 an electrically powered actuator operatively coupled for moving the valve element; and 
 a slug received within the valve element bore and operatively coupled to transfer a force produced by pressure in the valve element bore to a stationary component of the control valve thereby preventing the pressure in the valve element bore from affecting motion of the valve element, wherein the force is transferred without being applied to the valve element. 
 
     
     
       2. The electrohydraulic valve as recited in  claim 1  wherein the force is transferred to at least one of the valve body and the electrically powered actuator. 
     
     
       3. The electrohydraulic valve as recited in  claim 1  wherein the force is transferred to a housing of the electrically powered actuator. 
     
     
       4. The electrohydraulic valve as recited in  claim 1  wherein the force results from pressure within the first bore acting on the slug. 
     
     
       5. The electrohydraulic valve as recited in  claim 1  further comprising a member engaging the slug and the stationary component. 
     
     
       6. The electrohydraulic valve as recited in  claim 1  further comprising;
 a slot in the valve element; and 
 a member projecting through the slot and engaging the valve element and the stationary component. 
 
     
     
       7. The electrohydraulic valve as recited in  claim 1  wherein the slug remains stationary with respect to the valve body as the valve element slides within the first bore. 
     
     
       8. The electrohydraulic valve as recited in  claim 1  wherein the valve element further comprises an aperture that selectively provides a fluid path between the valve element bore and the first port. 
     
     
       9. The electrohydraulic valve as recited in  claim 1  wherein the valve body further comprises a second port in communication with the first bore; and as the valve element slides in the first bore the aperture provides a fluid path between the valve element bore and selectively the first port and the second port. 
     
     
       10. The electrohydraulic valve as recited in  claim 1  further comprising:
 an armature bore extending through the armature between a first chamber on one side of the armature and a second chamber on another side of the armature; and 
 a digressive damping element received within the armature bore and providing a variable orifice through which fluid flows bidirectionally between the first chamber and the second chamber, the variable orifice opening and closing in response to a difference in pressure between the first chamber and the second chamber. 
 
     
     
       11. An electrohydraulic control valve comprising:
 a valve body having a longitudinal bore there through forming a workport at one end of the longitudinal bore, and having a first port and a second port in communication with the longitudinal bore; 
 a valve element slideably received within the longitudinal bore and having first and second ends with a valve element bore extending into the valve element from the first end, and the valve element having an aperture that provides a fluid path between the valve element bore and selectively the first port and the second port; 
 a solenoid actuator operatively connected to produce movement of the valve element; and 
 a slug received within the valve element bore and operatively connected to transfer a force produced by pressure in the valve element bore to at least one of the valve body and a stationary component of the solenoid actuator thereby preventing the pressure in the valve element bore from affecting motion of the valve element, wherein the force is transferred without the force being applied to the valve element. 
 
     
     
       12. The electrohydraulic valve as recited in  claim 11  wherein the solenoid actuator is coupled to the second end of the valve element. 
     
     
       13. The electrohydraulic valve as recited in  claim 11  wherein the force is transferred to a housing of the solenoid actuator. 
     
     
       14. The electrohydraulic valve as recited in  claim 11  wherein the force results from pressure within the longitudinal bore acting on the slug. 
     
     
       15. The electrohydraulic valve as recited in  claim 11  further comprising a member secured to the slug and to the at least one of the valve body and the solenoid actuator. 
     
     
       16. The electrohydraulic valve as recited in  claim 11  further comprising;
 a slot in the valve element and opening into the valve element bore; and 
 a member projecting through the slot and attached the slug and to at least one of the valve body and the solenoid actuator. 
 
     
     
       17. The electrohydraulic valve as recited in  claim 11  wherein the slug remains stationary with respect to the valve body as the valve element slides within the longitudinal bore. 
     
     
       18. The electrohydraulic valve as recited in  claim 11  further comprising:
 an armature bore extending through the armature between a first chamber on one side of the armature and a second chamber on another side of the armature; and 
 a digressive damping element received within the armature bore and providing a variable orifice through which fluid flows bidirectionally between the first chamber and the second chamber, the variable orifice opening and closing in response to a difference in pressure between the first chamber and the second chamber.